AB1418 SYSTEMIC JUVENILE ARTHRITIS: EPIDEMIOLOGY AND LONG-TERM OUTCOME IN WESTERN AUSTRALIA.
Authors: J. Nossent, E. Kelty, H. Keen, D. Preen, C. Inderjeeth
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Systemic juvenile arthritis (S-JIA) is a rare but serious multiorgan autoinflammatory condition of childhood with an unpredictable disease course <sup>[1]</sup>. There is no data on disease frequency and outcome of S-JIA from the Pacific region. <h3>Objectives</h3> To investigate the epidemiological characteristics and long-term disease outcome in patients hospitalised with S-JIA in Western Australia (WA). <h3>Methods</h3> This population-level observational study includes children under the age of 16 with a recorded diagnosis of S-JIA (ICD-10-AM M08.20-M08.29) residing in WA between January 1999 and December 2014. Individual longitudinal health data regarding hospital admissions, ED visits, cancer and death were derived from the WA Rheumatic Disease Epidemiological Registry (WARDER) that contains routinely collected health data from public and private health care organisations for the entire state of WA. <h3>Results</h3> Based on 46 incident cases (71.7 % girls, median age 6.5 years) the average annual S-JIA incidence rate was 0.61/100,000 (CI 0.28-1.25), which did not no change significantly over time. Two thirds of incident cases were diagnosed in winter/spring and point prevalence for S-JIA reached 7.15/100,000 (CI 5.29-7.45) in 2014. Disease course was monocyclic in 42% of patients with MAS findings recorded in 4.4% and no case fatality observed during median follow up of 8years. Twenty-seven patients (58%) were readmitted for S-JIA with higher rates per 100 person years in boys (58.3/100, CI 44.5-74.9 vs 14.7 CI 9.9-20.9) (p&lt;0.001). Girls had significantly higher admissions rates for conditions not directly related to S-JIA (rate 103.3 vs 54.4, P&lt;0.001). At last follow-up, arthroplasty had been performed in 4% of patients and there was a high rate of ED visits (72.3/100 person years) after initial s-JIA admission. <h3>Conclusion</h3> The epidemiology of S-JIA in Australia is not unlike other countries <sup>[2]</sup>. While s-JIA incurred no deaths in the biologic era, S-JIA admission was followed by significant morbidity and health care usage over a lengthy period suggesting the need for extended care for s-JIA patients. <h3>References</h3> [1] Susan Shenoi, Carol A. Wallace. Diagnosis and Treatment of Systemic Juvenile Idiopathic Arthritis The Journal Of Pediatrics,2016,177,19-26. [2] Sigrid Thierry, Bruno Fautrel, Irène Lemelle, Francis Guillemin. Prevalence and incidence of juvenile idiopathic arthritis: A systematic review. Joint Bone Spine 81 (2014) 112–117 <h3>Acknowledgements</h3> Supported by an grant from the Arthritis Foundation of Western Australia and a project grant from Arthritis Australia (2021- 5101780) to JCN. We thank the Data Custodians of the Hospital Morbidity Data Collection (HMDC), Emergency Department Data Collection (EDDC), the Western Australian Cancer Registry (WACR), the State Registry of Births, Deaths and Marriages and the staff at Data Linkage Branch at the WA Department of Health for their assistance in provision of data. <h3>Disclosure of Interests</h3> None Declared.